rt

#include<iostream>
#include<algorithm>
using namespace std;
int arr[1000000]={0};//数组 
int main(){
	int n,m;
	cin>>n>>m;
	for(int i=1;i<=n;i++){
		cin>>arr[i];
	}
	sort(arr+1,arr+n+1);
	int s=0;
	for(int i=0;i<m;i++){
		int key;
		cin>>key;
		int id=lower_bound(arr+1,arr+1+n,key)-arr;
        if(id==n+1){
			s+=key-arr[n+1];
			continue;
		}
		if(id==1){
			s+=arr[1]-key;
			continue;
		}
		if(key-arr[id-1]<arr[id]-key){
				s+=key-arr[id-1];
			
		}else{
				s+=arr[id]-key;	
		}
	}
	cout<<s;
	return 0;
}